WBD is a "Windows Bounds Dictionary" file usually located in the "Rockstar Games\Grand Theft Auto IV\pc\data\maps\xxx_folder\xxx.img" WBN is a "Windows Bounds Nodes" file usually located in the "Rockstar Games\Grand Theft Auto IV\pc\data\maps\xxx_folder\xxx.img" these files are the method used within GTA-IV for collision files, early indications show that map model colision files are mapped in game "World coordinates"